大功率光纤放大器分段泵浦方式下的理论分析

利用数值算法计算了掺镱双包层光纤放大器分段泵浦方式下的稳态速率方程组,分析比较了双端泵浦和多段泵浦方式下的最佳光纤长度,最高温度和效率,并采用遗传算法对分布泵浦功率的大小和每段光纤长度同时进行了优化。结果表明,通过优化,大功率分段泵浦光纤放大器获得了较为平坦的温度分布,与双端泵浦相比,大大降低了最高工作温度,斜率效率略有下降。     

基于傅立叶变换的射频场分布测量方法

提出了一种基于傅立叶变换的射频场分布测量方法，该方法可以方便地测量出射频场的分布，其测量结果与样品的均匀度无关并且可以分别观测某个像素点处的层内射频场非均匀性或某个小区域内的射频场非均匀性.     

南开大学奇异性核物理的理论研究

简要介绍了南开大学核物理组在奇异性核物理方面的理论研究工作. 已经完成的工作有核介质内超子平均自由程的理论计算, 奇异性核物理方面已完成的其他4个理论研究课题是, 不同重子杂质对原子核的影响、重味重子超核、核物质内的eta-介子以及K介子原子核的性质.     

Teleportation of an n-bit one-photon and vacuum entangled GHZ cavity-field state

A scheme for teleporting an arbitrary n-bit one-photon and vacuum entangled Greenberger-Horne-Zeilinger （GHZ） state is proposed. In this scheme, the maximum entanglement GHZ state is used as a quantum channel. We find a method of distinguishing four Bell states just by detecting the atomic states three times, which is irrelevant to the qubit number of the state to be teleported.     

Well Crystallized α-GaOOH Nanocrystals Synthesized through Hydrothermal Routes and Their Properties

A facile hydrothermal process involving Ga(NO₃)₃·H₂O·NaN₃ solutions led to the formation of α‐GaOOH nano‐platelets. X‐ray diffraction (XRD) pattern revealed that the synthesized samples belonged to an orthorhombic crystal structure with lattice constants a=0.4510 nm, b=0.9750 nm and c=0.2965 nm. Transmission electron microscopy (TEM) studies showed that α‐GaOOH displayed the morphologies of an eccentric platelet‐like structure with 60–120 and 200–300 nm in the short and long axes, respectively. The average thickness of products was about 70 nm through scanning electron microscopy (SEM) images. The ultraviolet absorption of the samples was at 214 nm. The prepared α‐GaOOH nano‐platelets exhibited a broad emission band from 220 to 400 nm with a maximum at 343 nm under short UV excitation of 200 nm. Fourier transform infrared (FTIR) spectrum confirmed the existence of Ga₂O and Ga–OH bending modes. A possible mechanism for the formation of α‐GaOOH nano‐platelets was discussed briefly.     

辅酶Q10及其杂质结构鉴定

辅酶Q10是1975年初次从牛心肌中分离而得的一种脂溶性结晶,属泛醌类化合物.具有提高人体免疫力,增强抗氧化能力,延缓衰老等功能.可用于心血系统疾病、肝病等辅助治疗.近年来,国内外也将辅酶Q10广泛用于营养保健品及食品添加剂.     

增韧环氧树脂的动态裂纹扩展研究

本文主要进行了环氧及增韧环氧树脂的断裂韧性及裂纹快速扩展的试验研究。试验过程中采用了ＧＬＣ－１型高速裂纹扩展测试仪来测试裂纹的扩展速度,得到在裂纹扩展过程中裂纹扩展速度曲线。本文结合不同的计算公式及有限元分析方法,讨论了各个确定断裂韧性公式的准确程度,发现传统的静态断裂韧性的分析方法所得到的结果偏大,有一定的危险性,建议使用试验与数值计算相结合的方法;同时还发现增韧不仅可以提高材料的静态和动态断裂性能,而且在裂纹扩展过程中可以起到减缓裂纹扩展的作用     

面向工程教育的高分子物理

"高分子物理"教育是以物理、化学、数学等学科知识为基础,面向工程教育的高分子物理课程面临着与理科教育不同的培养对象和不同的培养目标。本文以华南理工大学"高分子材料与工程"专业发展历程和教学改革为例,结合"高分子物理"自身的特点和定位,提出了"高分子物理"要在工程教育的各专业课程之间起桥梁作用,建立理论与实践结合的高分子物理课程。就目前工程教育的"高分子物理"面临的多元化就业和职业化课程的矛盾、工程教育和行业对接的矛盾、教学方式方法课程深度和广度的矛盾、通选基础课程和专业基础课程缺乏有效结合的矛盾等进行了分析和讨论。     

Isolation and Characterization of Two Novel Gene Encoded Alkaline Esterases from an Alkaline Soil Metagenomic Library

<正>The development of industrial biotechnology has created an increasing demand for alkaline lipolytic enzymes with functional diversity.In this study,an alkaline soil metagenomic library was constructed to search for new lipolytic enzymes.Two novel gene encoded alkaline esterases(designated as estA and estB) were isolated by functional screening from the library.The estA gene consisted of 834 bp and coded for 277 amino acids with a molecular mass of 29998.Amino acid sequence homology analysis indicates that EstA belongs toα/βhydrolase fold family 4.4(abH4.4),with EstA being the smallest member of that family yet reported.The estB gene consisted of 1185 bp and encoded 394 amino acids with a theoretical molecular mass of 40090.Its conserved domain analysis shows that EstB belongs to the GDSL hydrolase superfamily.Both EstA and EstB exhibit only moderate identity(38%) in amino acid sequence to the known lipolytic enzyme genes in the database.The two genes were respectively expressed in Escherichia coli and the protein products were purified for functional characterization.While the expressed EstA did not exhibit the functional properties that were superior to those of other esterases previously reported,the EstB was stable at temperature up to 45℃and its maximum activity was measured to be 53.6 U/mg at pH=10.Both the enzymes have further enriched the diversity of the lipolytic enzymes database and also appear to be promising biocatalysts for potential biotechnological application.     

二茂铁表面活性剂的电化学行为

以循环伏安法为主要手段,研究了具有可逆特性的二茂铁表面活性剂(N,N-二甲基二茂铁甲基十四烷基溴化铵,Fc14)在0.1 mol/L Na2SO4溶液中形成胶束对电化学行为的影响,并讨论了pH、扫描速度及浓度对Fc14电化学行为的影响.结果表明,Fc14在pH=2左右具有良好的可逆变化特性,在氧化态(I2+)与还原态(I+)之间可实现自由转换;Fc14在玻碳电极上的logIpc~logv呈现良好的线性关系(R20.991).当Fc14的浓度大于2 mmol/L时,电化学氧化过程以扩散控制为基本特征;当浓度小于0.2 mmol/L时,电极吸附现象的特征趋于明显.与此同时,Ipc和扩散系数(D)在Fc14的临界胶束浓度(CMC)附近出现突变,这与Fc14表面张力变化趋势相吻合.